如何 link docker 容器与 docker-compose 相互连接

Question

我必须使用 docker-compose 设置一个 mongo 副本集。对于副本集，容器必须相互了解。

我试过docker-compose.yml

    dbreplicasetpart1:
      image: mongo:2.6.8
      expose:
        - '27018'
      links:
        - replicasetpart2
        - replicasetpart3
      cap_add:
        - NET_ADMIN

    dbreplicasetpart2:
      image: mongo:2.6.8
      links:
        - replicasetpart1
        - replicasetpart3
      expose:
        - '27019'
      cap_add:
        - NET_ADMIN
...

我收到循环导入消息。但是，如果我删除 back-link 到 dbreplicasetpart1，我将无法从 dbreplicasetpart2 ping 到 dbreplicasetpart1。解决方法是什么？

Answer 1

你应该使用大使模式：

https://docs.docker.com/engine/admin/ambassador_pattern_linking/

基本上，您创建了一个中间组件，将它们连接在一起。您可以看到我们使用 Spring Cloud 的 Eureka 发现服务的示例：

ambassador:
  image: cpuguy83/docker-grand-ambassador
  volumes:
    - "/var/run/docker.sock:/var/run/docker.sock"
  command: "-name eureka_1 -name eureka2_1 "

eureka:
  links:
    - "ambassador:eureka2"

eureka2:
  links:
    - "ambassador:eureka"

为简单起见，我只复制了链接

Answer 2

我们想到了与大使一起使用该解决方案。这确实是更舒适的解决方案。适合我们的配置：

amba1:
  image: cpuguy83/docker-grand-ambassador
  volumes:
    - "/var/run/docker.sock:/var/run/docker.sock"
  command: "-name cucumber_dbreplicasetpart1_1"

amba2:
  image: cpuguy83/docker-grand-ambassador
  volumes:
    - "/var/run/docker.sock:/var/run/docker.sock"
  command: "-name cucumber_dbreplicasetpart2_1"

amba3:
  image: cpuguy83/docker-grand-ambassador
  volumes:
    - "/var/run/docker.sock:/var/run/docker.sock"
  command: "-name cucumber_dbreplicasetpart3_1"

dbreplicasetpart1:
  image: 'mongo:2.6.8'
  hostname: dbreplicasetpart1
  command: >
    bash -c
    '
      mongod --fork --logpath mongo.log --smallfiles --replSet rs1
      echo "
        printjson(
          rs.initiate(
            {
              _id : \"rs1\",
              members : [
                {_id : 0, host : \"dbreplicasetpart1:27017\"},
                {_id : 1, host : \"dbreplicasetpart2:27017\"},
                {_id : 2, host : \"dbreplicasetpart3:27017\"},
              ]
            }
          )
        );
      " | mongo;
      tail -f mongo.log
    '
  links:
    - "amba2:dbreplicasetpart2"
    - "amba3:dbreplicasetpart3"

dbreplicasetpart2:
  image: 'mongo:2.6.8'
  hostname: dbreplicasetpart2
  command: >
    bash -c
    '
      mongod --fork --logpath mongo.log --smallfiles --replSet rs1
      echo "
        printjson(
          rs.initiate(
            {
              _id : \"rs1\",
              members : [
                {_id : 0, host : \"dbreplicasetpart1:27017\"},
                {_id : 1, host : \"dbreplicasetpart2:27017\"},
                {_id : 2, host : \"dbreplicasetpart3:27017\"},
              ]
            }
          )
        );
      " | mongo;
      tail -f mongo.log
    '
  links:
    - "amba1:dbreplicasetpart1"
    - "amba3:dbreplicasetpart3"

dbreplicasetpart3:
  image: 'mongo:2.6.8'
  hostname: dbreplicasetpart3
  command: >
    bash -c
    '
      mongod --fork --logpath mongo.log --smallfiles --replSet rs1
      echo "
        printjson(
          rs.initiate(
            {
              _id : \"rs1\",
              members : [
                {_id : 0, host : \"dbreplicasetpart1:27017\"},
                {_id : 1, host : \"dbreplicasetpart2:27017\"},
                {_id : 2, host : \"dbreplicasetpart3:27017\"},
              ]
            }
          )
        );
      " | mongo;
      tail -f mongo.log
    '
  links:
    - "amba1:dbreplicasetpart1"
    - "amba2:dbreplicasetpart2"

Answer 3

更新为 Docker 1.10

Docker 1.10 允许在 compose 文件中定义网络。这是更新后的代码

version: "2"

services:
  replica1:
    image: mongo:2.6.8
    container_name: replica1
    networks:
      - my-net
    ports:
      - "27018"
    environment:
      REPLICA2_URL: "http://replica2:27019"
  replica2:
    image: mongo:2.6.8
    container_name: replica2
    networks:
      - my-net
    ports:
      - "27019"
    environment:
      REPLICA1_URL: "http://replica1:27018"

networks:
  my-net:
    driver: bridge

Docker 1.9

的上一个答案

从 Docker 1.9 开始，解决方案是创建自定义网络并将其传递给 docker-compose up 命令。

创建网络 docker network create --driver bridge my-net
在 docker-compose.yml 文件中将该网络引用为环境变量 (${NETWORK})。例如：

```

replica1:
  image: mongo:2.6.8
  container_name: replica1
  net: ${NETWORK}
  ports:
    - "27018"
  environment:
    REPLICA2_URL: "http://replica2:27019"

replica2:
  image: mongo:2.6.8
  container_name: replica2
  net: ${NETWORK}
  ports:
    - "27019"
  environment:
    REPLICA1_URL: "http://replica1:27018"

```

注意http://replica1:27018中的replica1将解析为replica1服务（容器）的ip地址。无需硬编码 ip 地址； replica1 的条目会自动添加到 replica2 容器的 /etc/host 中。 replica1 容器也是如此。 Docker 将在其 /etc/host 文件中为 replica2 添加一个条目。

调用 docker-compose，将您创建的网络传递给它 NETWORK=my-net docker-compose up -d -f docker-compose.yml

我创建了一个 bridge network above which only works within one node (host). Good for dev. If you need to get two nodes to talk to each other, you need to create an overlay network。不过原理一样。您将网络名称传递给 docker-compose up 命令。

Answer 4

以下是 Docker 1.7.1 中仍然有效的内容（以防你坚持使用 CentOS 6）：

etcd:
  image: elcolio/etcd:latest
skydns:
  image: outrider/skydns
  links:
    - etcd
  environment:
    ETCD_MACHINES: "http://etcd:4001"
    SKYDNS_DOMAIN: "docker"
    SKYDNS_PATH_PREFIX: my
    SKYDNS_NDOTS: 0
    SKYDNS_VERBOSE: "true"
    SKYDNS_ADDR: 0.0.0.0:53
  expose:
    - 53

my-service:
    image: alpine
    command: sh -c "dns_add my-service && ping my-service"
    links:
      - etcd
      - skydns

dns_add 脚本：

#!/usr/bin/env sh

# This script configures resov.conf to use
# "skydns" name server with "docker" domain
# and adds a service name specified in the first argument
SERVICE_NAME=

waitforit () {
  HOST=
  PORT=
  TIME_OUT=${3:-30};
  END=$(($(date "+%s+$TIME_OUT")))
  while [ $(date "+%s") -lt $END ]
    do nc -z -w1 $HOST $PORT && break
  done
  return $END
}

# Use skydns to resolve names
echo "nameserver `resolveip -s skydns`" > /etc/resolv.conf
echo "search docker" >> /etc/resolv.conf

# Put yourself to DNS
ETCD_HOST=etcd
ETCD_PORT=4001
waitforit $ETCD_HOST $ETCD_PORT
HOST_IP=`resolveip -s $HOSTNAME`
apk update && apk add curl
curl -XPUT http://$ETCD_HOST:$ETCD_PORT/v2/keys/my/docker/$SERVICE_NAME -d value="{\"host\":\"$HOST_IP\"}"

这里有一个解释：

我们在容器中搭建了自己的DNS服务器
我们将容器配置为使用该服务器
我们使用特殊的 HTTP 请求配置该 DNS 服务器

Answer 5

不更新 docker-compose.yml 文件，

docker network connect docker-compose-network-you-want-to-connect conatianer-name-from-another-docker-compose

更多here

如何 link docker 容器与 docker-compose 相互连接

how to link docker container to each other with docker-compose

docker

docker-compose